1. Field of the Invention
The present invention relates to an apparatus for controlling the radial play of a roller bearing by adjusting the quantity of oil passing through its drained outer ring.
2. Description of the Background
Some roller bearings, particularly those rotating at very high speeds, are continually lubricated by a dedicated circuit. Under normal circumstances the oil drains away outside the roller bearing by being laterally expelled by the forces of inertia imparted to it by the rotating components. However, another design exists in which the oil leaves the roller bearing radially through channels that are pierced through one of the rings, usually the outer ring. This roller bearing (or this ring) is said to be drained. One of the aims of this design is to reduce or even eliminate oil being laterally propelled out of the roller bearing and thereby eliminating the need for lubricant recovery scoops provided near the roller bearing. Another even more important advantage is that the drained ring is cooled more effectively by the lubricant. The outer ring of a roller bearing usually tends to heat to a higher degree than the inner ring and the difference in temperature between the two rings can be several degrees when the roller bearing rotates at a steady speed. In a standard roller bearing where the outer ring is drained, the difference in temperature is reduced, therefore the play that the differential thermal expansion causes around the ball bearings or more generally around the roller bearing components is also reduced. It may be concluded that correct application of drainage enables the play around the roller bearing to be reduced and consequently improves the operation.
Some drainage circuit construction methods have been suggested by the present applicant in a previous French patent (2 740 187 A). In the present patent discussion centers around the means for adjusting the drained output in order to modify the operating conditions of the roller bearing and particularly the radial play.